Ev::suspend

说明

All timer watchers will be delayed by the time spend between
suspend
and
resume
, and all
periodic
watchers will be rescheduled(that is, they will lose any events that would
have occurred while suspended).

After calling
Ev::suspend()
it is not allowed to call any function on the given loop other than
Ev::resume()
. Also it is not allowed to call
Ev::resume()
without a previous call to
Ev::suspend()
.